Add script to help with testing interactive examples.

Small script I've been using to help test examples that require human interaction.  It opens each file in a given examples directory, waits for user input before opening the next example to see if things had displayed correctly, then logs any errors to a log file.
you can use `six` instead, check this line of report_issue function: https://github.com/ContinuumIO/bokeh/blob/master/bokeh/__init__.py#L142